Thin film transistor-liquid crystal display (TFT-LCD) has such advantages as small size, low power consumption and radiation-free, which has been developed rapidly at recent years and plays a leading role in the flat panel display market. An array substrate is a major structure of the TFT-LCD, including gate lines and data lines intersected to each other and configured to define a plurality of pixel areas. Each pixel area corresponds to a thin film transistor so as to control a display of the pixel area. The larger a width to length ratio (W/L) of a channel of the thin film transistor is, the larger a turn-on current may be, and then a performance of the thin film transistor may be better. In order to reduce an adversely influence on an aperture ratio, the thin film transistor is usually arranged on the gate line.
With development of the display technology, a requirement of resolution of a user is improving, such that a larger aperture ratio and a smaller thin film transistor are desired. For a small size thin film transistor, it is very difficult to realize a channel with a large width to length ratio, and thus a performance of the thin film transistor is adversely influenced.